After her son and daughter were born, Laski began writing in earnest. Marghanita was an omnivorous reader; from 1958 onwards she became a prolific and compulsive contributor to the Oxford English Dictionary and by 1986 had "carded" around 250,000 quotations,[3] making her (according to Ilan Stavans) "the supreme contributor, male or female, to the OED".[4] In the 1960s, Laski was the science fiction critic for The Observer.[5] Elected Vice Chairwoman of the Arts Council in 1982, she served as chair of its Literature Panel between 1980 and 1984.[6]

Anthony Boucher described her novella The Victorian Chaise Longue as "an admirably written book, highly skilled in its economic evocation of time, place and character -- and a relentlessly terrifying one."[8]Ecstasy: A Study of Some Secular and Religious Experiences has been compared to The Varieties of Religious Experience by William James in its importance.[4]